That morning jolt of coffee could be harmful for those being treated for high blood pressure.
A research team from Western University and Lawson Health Research Institute measured how occasional coffee consumption in individual patients impacted the action of calcium channel blockers, a commonly prescribed class of blood-pressure lowering medication.
The first phase of this study was published in the American Journal of Hypertension and showed the combination of coffee plus a calcium channel blocker, felodipine, led to elevated blood pressure compared to felodipine alone. Calcium channel blockers relax and widen blood vessels, making it easier for blood to flow and in turn lower your blood pressure.
“Even one cup of coffee containing a relatively low amount of caffeine remarkably compromised the anti-hypertensive effect of this drug at the maximum recommended dose,” said Dr. David Bailey, Lawson scientist and researcher at Western’s Schulich School of Medicine & Dentistry.
“If you wanted to overcome the effect of the coffee, you had to double the dose of this anti-hypertensive drug which could increase the risk of unwanted excessive drug effects, particularly during the period when coffee is not consumed.”
Previous studies have shown that coffee and caffeine don’t have much effect on blood pressure for those who drink coffee on a regular basis because of tolerance development.
However, this study demonstrated that just two days abstaining from coffee was sufficient time to eliminate caffeine from the body and to increase blood pressure on subsequent coffee exposure.
Just one cup of coffee caused the maximum increase in blood pressure and it occurred by one hour after intake and lasted for several hours.
“If you are an occasional coffee consumer and you have a cup of coffee twice or less a week, you have this risk of increased blood pressure which can be substantial in certain individuals,” Bailey said.
“We want to raise awareness about the potential risks for the high number of people who are occasional coffee drinkers.”
